1. Field of the Invention
This invention relates to a system terminating process effected at the time of power failure or outage in a system for protecting a computer from the outage by use of an uninterruptive power supply having a battery, and more particularly to a system termination processing method and device for improving the operation efficiency of the uninterruptive power supply.
2. Description of the Related Art
For example, in order to stably hold data, a computer known as a network server is connected to an uninterruptive power supply having a battery to protect data from being destroyed at the time of outage in many cases.
Conventionally, in the system terminating process effected at the time of outage in a system using the uninterruptive power supply, the "emergency system terminating process" was effected as the emergency process only when the remaining capacity of the battery in the uninterruptive power supply was reduced to an extremely small value. The emergency system terminating process saves information relating to data held in the respective portions of the system, memory contents, the states of the respective portions of the system which may be destroyed by the stoppage of electric power supply into a storage device such as an external storage device in which the content will not be destroyed even if no electric power is supplied, and then, shuts off the power supply of the computer.
In the above emergency system terminating process, the monitoring operation of, for example, comparing the remaining capacity of the battery in the uninterruptive power supply with the electric power necessary for processing the unprocessed portion of the system terminating process was not effected. Therefore, even if the supply of electric power of the power supply was recovered during the system terminating process, the system terminating process was completely effected until the power supply of the system was shut off.
Further, even if the power supply was recovered after the power supply of the computer was interrupted by the emergency system terminating process and the supply of electric power of the power supply was recovered, the system could not be used again if the power supply of the computer was not manually turned ON.
As described above, conventionally, in the system using the uninterruptive power supply, the system terminating process effected at the time of outage, the emergency system terminating process which is an emergency process was effected only when the remaining capacity of the battery in the uninterruptive power supply became extremely small, and the control operation was not effected by reference to the remaining capacity of the battery in the uninterruptive power supply together with the execution stage of the system terminating process. Therefore, even if the power supply was recovered during the system terminating process, the power supply of the system was shut off by the system terminating process. Further, when the power supply was recovered after the power supply of the computer was shut off by the emergency system terminating process, the power supply of the computer was turned ON by the manual operation.
That is, in the conventional system terminating process, only when the remaining capacity of the battery in the uninterruptive power supply became less than a preset value, the system terminating process was effected. For this reason, the amount of electric power which could be supplied until the supply of electric power to the system was completely stopped or time taken until the supply of electric power was stopped was determined by the preset value of the remaining capacity of the battery for starting the system terminating process. Therefore, whether all of the processes (for saving entire information which might be destroyed by the outage) of the system terminating process could be effected or only the minimum amount of processes (for saving the most important information of minimum amount which could not be recovered by the other process) of the system terminating process could be effected was practically determined according to the preset value of the remaining capacity of the battery for starting the system terminating process. Further, when the power supply was restored and the supply of electric power was recovered during the system terminating process, the system had to be restarted after the system terminating process was first completely effected. When the power supply was restored and the supply of electric power was recovered after the power supply of the computer was shut off by the system terminating process, the operator was required to turn ON the power supply in order to restart the system.